# Aisles API versioning and deprecation policy

- The major version is in the path: https://aislesinventory.com/api/v1/. Within v1, fields are only added, never removed or renamed; ignore fields you do not use.
- A change that would break callers gets a new path (/api/v2/). The old version keeps working for at least 6 months after the new one ships.
- Before a version stops, its responses carry a `Deprecation` header (RFC 9745) from the day it is deprecated and a `Sunset` header (RFC 8594) with the date it stops, and this page lists the dates. Nothing is deprecated now.
- The MCP server (https://aislesinventory.com/mcp) follows the same rule for its tools: new optional parameters only; a tool is never removed without the same notice.
- Changes are announced here and on https://aislesinventory.com/developers.